Diagnosis of Herpetic Uveitis is Aided by Confocal Microscopy with the HRT RCM

Abstract

Purpose Herpetic uveitis (HU) is a frequent infectious cause of anterior uveitis. A definite diagnosis can be obtained by anterior chamber puncture and PCR, an invasive procedure not all patients consent to. We hypothesized that patients with HU typically have high amounts of dendritiform inflammatory cells (DCs) in their corneal subepithelial nerve plexus (SNP),which are detectable by in vivo confocal microscopy and distinguish HU from other uveitis types. Methods Patients with clinical suspicion of HU without keratitis and patients with Fuchs Uveitis Syndrome (FUS) were imaged with the Rostock Cornea Module attachment on the HRT III (HRT‐RCM)(Heidelberg Engineering) on both eyes. DCs in the SNP were counted by two observers using a cell counting software. Means of the cell counts were used for analysis. Diagnosis of HU was confirmed by anterior chamber puncture or by clinical improvement due to Acyclovir therapy. Statistical significance was assessed with a Kruskal‐Wallis or a Mann Whitney U test,when appropriate. Results Patients with HU showed significantly higher amounts of DCs in their affected eyes (93.3±10.6 cells/mm2, Mean±SEM, n=10) but also in their unaffected eyes (59±25 cells/mm2, n=7), than patients with FUS, who had an average DC‐density of 46.4±10.4 cells/mm2(n=15) in their affected and 21±6 cells/mm2(n=15) in their unaffected eyes. Conclusion High amounts of DCs in the corneal SNP were a typical finding in herpetic AU. Much lower numbers of DCs were present in FUS, a clinical similar uveitis type presumably also of viral origin. Imaging corneas of patients with clinical suspicion of HU with the HRT‐RCM is a non‐invasive, low risk technique which can be a useful addition in distinguishing HU from other anterior uveitis aetiologi